______,In a large stock pot, saute the curry paste, garlic, lemon grass, lime leaves and kha in the vegetable oil for two minutes.,Stir in chicken broth and bring to a boil.,While broth is heating, slice the chicken breast and toss it in cornstarch. The amount of cornstarch doesn't need to be exact; just make sure the slices are evenly coated and shake off any excess.,Add chicken to boiling broth, stir gently, and bring back up to a simmer.,Stir in mushrooms, coconut milk, fish sauce and lime juice. Bring back up to a simmer, stirring gently a few times, then cut the heat off and you're ready to serve.,Garnish with fresh cilantro and serve.